1. Field of the Invention
The present invention relates to a swallowing estimation device which estimates a swallowing movement, an information terminal device for obtaining information necessary for estimation of the swallowing movement, and a storage medium having stored therein a program which provides a computer with a swallowing estimation function.
2. Disclosure of Related Art
Japanese Laid-Open Patent Publication No. 2013-17694 discloses a technology which analyzes the frequency of biological sound obtained from a larynx portion, and distinguishes among swallowing, coughs and utterance based on frequency characteristics thereof. Meanwhile, “Non-restrictive monitoring of swallowing frequency of elderly individuals” in an academic journal “The Journal of Japanese Occupational Therapy Association” Vol. 31(1) PP. 52 to 59 (Non-patent literature) issued by the Japanese Association of Occupational Therapists in February in 2012 discloses the following technology. That is, with respect to pulse groups each consisting of pulses obtained by converting biological sound collected by a larynx microphone into pulses, a pulse group in which each pulse width is less than or equal to 60 msec and the number of pulses is less than or equal to 20 is determined as representing a swallowing movement.
Before performing swallowing estimation, first, it is necessary to collect information such as biological sound from a subject. In this case, in order not to restrict the subject as much as possible, it is desirable that the apparatus and the like to be worn by the subject are as simple as possible. Accordingly, it becomes possible to collect information for swallowing estimation from the subject in a living environment. However, when information is collected in a living environment in this manner, information of various sounds that contaminate swallowing sound is collected, such as household noises, sounds during eating and drinking, conversations, sounds generated when the neck is rotated, in addition to biological sound generated during swallowing. These noises cause erroneous swallowing estimation, resulting in reduced estimation accuracy of swallowing.